Gastrin Bombesin

Gastrin is the name of the neuropeptide that carries the
message of fear from the amygdala to the gut. Upon arrival in the
gut, gastrin gives rise to dyspepsia — those gut-wrenching feelings
of 'butterflies in the stomach' that we experience as qualms, quease,
anxiety, nausea, disgust, anger, biliousness or feeling galled.

Bombesin is the name of the neuropeptide that carries the
message of fear from the amygdala to the periphery of the body. Upon
arrival, bombesin causes a shutdown of the blood supply to the skin,
wherupon our color blanches, we get goose bumps, and we feel 'chilled
out' (white as a ghost). Creepy. Shiver me timbers.